module teapo.boot {

​

  export class StorageLoader {

​

    private _domStorage: storage.attached.dom.LoadStorage;

​

    private _callbacks: StorageLoader.Callbacks = null;

​

    private _indexedDBDetectCompleted = false;

    private _webSqlDetectCompleted = false;

    private _persistenceName: string = null;

    private _persistence: storage.attached.LoadStorage = null;

​

    constructor(

      private _dom: Dom,

      private _storageElement: HTMLElement,

      private _uniqueKey: string) {

    }

​

    loadStorage(callbacks: StorageLoader.Callbacks) {

      if (this._callbacks)

        throw new Error('Cannot load storage twice.');

​

      this._callbacks = callbacks;

​

      try {

        this._domStorage =

        new storage.attached.dom.DetectStorage(this._storageElement, this._dom.documenOverride).

          detectStorageSync();

      }

      catch (err) {

        this._callbacks.detectionComplete(err, null, null, null);

        return;

      }

​

      var detectIndexedDB = new storage.attached.indexedDB.DetectStorage();

      var detectWebSQL = new storage.attached.webSQL.DetectStorage();

​

      detectIndexedDB.detectStorageAsync(this._uniqueKey, (error, load) => {

        this._indexedDBDetectCompleted = true;

​

        if (error) {

          if (!this._webSqlDetectCompleted)

            return; // wait for webSQL, it can still succeed

​

          // revert to webSQL results

          this._detectCompleted();

        }

        else {

          this._persistence = load;

          this._persistenceName = 'indexedDB';

​

          this._detectCompleted();

        }

      });

​

      detectWebSQL.detectStorageAsync(this._uniqueKey, (error, load) => {

        this._webSqlDetectCompleted = true;

​

        if (this._persistence)

          return;

​

        this._persistence = load;

        if (this._indexedDBDetectCompleted)

          this._detectCompleted();

      });

    }

​

    private _detectCompleted() {

      var loadingFromPersistence = this._persistence && this._persistence.editedUTC > this._domStorage.editedUTC;

​

      var sourceLoad = loadingFromPersistence ? this._persistence : this._domStorage;

      var targetLoad = loadingFromPersistence ? this._domStorage : this._persistence;

      this._callbacks.detectionComplete(

        null,

        this._persistenceName,

        sourceLoad.editedUTC,

        loadingFromPersistence);

​

      var byFullPath: { [fullPath: string]: { [property: string]: string; }; } = {};

      var totalFileCount = 0;

      var loadedFileCount = 0;

      sourceLoad.load({

        files: (fileCount) => {

          totalFileCount = fileCount;